A. Field of the Invention
The device of the present invention generally relates to a spark gap for a surge arrester and, more particularly, to a current limiting spark gap for a valve type surge arrester.
B. Description of the Prior Art
Valve type surge arresters having a spark gap electrically connected in series with one or more blocks of non-linear resistance valve material and electrically connected between an electrical power line conductor and ground are well known in the prior art. Many prior art spark gaps utilize magnetic means, such as permanent magnets or electrical coils for elongating electrical arcs to develop high arc voltages and thus facilitate the interruption of power follow current.
Other prior art spark gaps utilize merely the conductive electrode and arc chamber configurations to elongate power follow arcs and omit supplementary magnetic means, such as the above-mentioned permanent magnets and electrical coils. Examples of the latter type of spark gaps are illustrated in U.S. Pat. Nos. 2,917,662; 3,242,376; 3,259,780; and 3,504,226. Generally, the spark gaps illustrated in the above-identified patents suffer from one or more deficiencies. For example, a common deficiency is the unnecessarily complex and expensive configuration of the spark gap. In addition, many of the spark gaps do not develop sufficiently high arc voltages to significantly enhance power follow current limitation.